During the repair phase of healing, stretching is a preferred technique. Why?

The inflammatory phase has ended when the repair phase starts. In the repair phase, granular substance, collagen, and fibrinogen fill in the lesion and the formation of the scar begins, but it's too fragile for any vigorous techniques. So mild stretching and range of motion combined with MICE (movement, ice, compression, elevation) are indicated to help organize the fibers linearly. It's during the remodeling phase when more vigorous techniques are applied and the focus is to break down the scar tissue a little and create functional inflammation to strengthen the scar.